• Journal of Bio-Environment Control
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• v.26 no.2
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• pp.100-107
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• 2017

This experiment was carried out to analyze the effects of substrate reuse on the growth and yield of summer paprika in cyclic hydroponics. The test group was divided into a new coco slab, one year reused coco slab two year reused coco slab based on 30% nutrient solution reuse, and was performed from April 18 to November 31, 2016 for 30 weeks. As a result, plant height of early growth was that the 2 year reused slab was longer than the new slab but the final growth period was 56.58 cm shorter. First group flower position was that reused slab was shorter by 2.92 cm than the new slab and the second group flower position was 0.31 cm long. The relative internode length of early growth, when the reused slab was used, the imbalance in the late growth stage was increased compared with the use of the new slab. The number of growth nodes in the 1 and 2 year reused slab was the smallest with 27.4 nodes. However, the number of harvested nodes did not show the difference in the test group, and the ratio of harvested that the 2 year reused slab was the highest at 26.8%. The ratio of unmarketable fruit tended to increase as the growth progressed. Fresh weight was 227.7g for new slab, 219.2g for 2 year reused slab and 21.2g for 1 year reused slab. The dry weight of the new slab increased with the reuse of the slab. It was 17.13g for new slab, 18.26g for 1 year reused, and 19.28g for 2 year reused. The average water content of the entire growth period was smaller as the slab was reused, and the 1 year reused slab was about 20g less than the 2 year reused slab. This trend was steadily occurring throughout the entire growing season. Especially, the reused slab for 1 year was less than 60g after 3 groups compared to other test groups. In conclusion, If will control seriously occurrence of unmarketable fruits by weakening after medium growth in summer-cultivated paprika in EC-based recycling hydroponic cultivation with reused cocopeat substrate, It is not what I have to worry that decrease of the yield and deterioration of the quality due to the change of physical and chemical properties of the slab and the pathogenic bacteria infection.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.3
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• pp.127-135
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• 2001

Achieved to grasp possibility to use compost that make food waste and sawdust (bulking agent) by raw material in this research droopingly to bulking agent calamity. To be kept by aerobic experiment method to 4 composting device that air is supplied Food Waste + Sawdust, Livestock Feces + Sawdust, Food Waste + Compost, Livestock Feces + Compost free medical care and investigated composting sledding and temperature, pH, the moisture rate, heavy metals item etc. Judged that food waste of the moisture rate mix experiment result food waste input (food waste and sawdust composting done material mean) compost happened after resources anger as bulking agent food waste and Livestock Feces quantity is 72~77%, because axis dries to promote optimum composting progress appearing by 64~65%, thing which use need and was difficult to set salt 1% that is by-product compost standard when use compost as bulking agent of food waste but by dilution effect of Livestock Feces quantity using compost being expose that preservation is available by standard low because salt content density of done compost becomes found possibility that can solve salt content problem.

• Composites Research
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• v.12 no.5
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• pp.54-64
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• 1999

This study investigated the impact behaviors of the stitched sandwich composites under the low energy impact by the use of drop weight impact tester. These sandwich composites condidted of the glass fabric faces with a urethane foam core. The upper face and the lower face were stitched to combinr through the core thickness direction using the polyester reinforcements. Four types of the stitched sandwich composites, each having a different core thickness, were tested to determine the effects of the core thickness. The impact conditions were changes with the variations of the mass and drop height of the impact tup. The test results showed that the core thickness and the impact condidtions such as the drop height and the mass of the impact tup affected the impact force, the contact time, and the strain behaviors of the stitched sandwich composites. The stitched sandwich composites are able to avert the damage and also maintain the structural integrity even thouth the presence of the damage owing to the through-the-thickness reinforcements. However, it is important to improve the wetting ability of the stitched reinforcements so that the conventional structures are substituted for the stitched sandwich composites effectively.

• Composites Research
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• v.23 no.6
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• pp.19-25
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• 2010

This paper describes the optimum design of bolt locations for metal joint parts of railway bogie frame made of glass fiber/epoxy 4-harness satin woven laminate composite and PVC foam core. The optimum design analysis was done by sub-problem approximation method using Ansys Parameter Design Language(APDL). The sub-modeling method was introduced to conduct the detailed recalculation for the only target parts and reduce calculating time. The structural analysis for composite bogie frame was performed according to JIS E 4207. The results showed that the optimum design analysis using sub-modeling method was able to obtain faster and more precise results than that of the entire model by the control of mesh size for the target parts, and the maximum Von-Mises stress has been reduced in comparison with its original dimensions due to the optimum design of bolt locations.

• Korean Journal of Plant Tissue Culture
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• v.24 no.3
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• pp.125-128
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• 1997

The most effective cytokinin source for adventitious shoot regeneration of in vitro grown leaves from 'Gala' apple was BA with the concentration of 4.0 mg/L, while auxin source was IAA, IBA and NAA with the concentration of 0.1 mg/L, respectively. As the result of combinational treatment of BA and NAA, 6.0 or 8.0 mg/L BA with 0.5 mg/L NAA was effective for adventitious shoot regeneration from leaf tissues of 'Gala', 0.1 mg/L NAA + 8.0 mg/L BA and 1.0mg/L NAA + 8.0 mg/L BA for internode, and 0.1 mg/L NAA + 4.0 mg/L BA for petiole.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.84-88
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• 2015

경인 아라뱃길은 국내에서 운영된 사례가 없는 기수역 운하로서 유량 및 수환경 관리 등을 포함한 수질관리 상황을 종합적으로 평가하기 위한 대책이 필요하다. 또한 경인 아라뱃길로 유입되는 오염원에 대한 현황 및 현장조사를 실시하고, 유입 오염원인을 정확히 파악하는 것이 중요하다. 따라서 경인 아라뱃길 유역의 수질조사 및 분석, 수질예측을 통해 수질관리 방안을 제시하였다. 분석결과, 홍수시 경인 아라뱃길로 유입되는 굴포천의 DO, BOD, SS는 삼정천의 영향으로 상승하였다. 삼정천은 굴포천 상류에서 부천시와 인천시의 관할 행정구역 면적에 비해 인구밀도가 높고 축산 농가 및 산업계로 인한 미처리 유출수에 의해 굴포천에 직 간접적인 영향을 미치고 있는 것으로 판단된다. 또한 굴포천 하수처리장 방류 이후 BOD, T-N, T-P의 경우 급상승하였다. 따라서 굴포천 중류의 부천시 삼정동과 인천시 계양구 내 하수 및 폐수를 하수처리장을 통해 배출할 수 있는 공동처리장 운영 등의 처리 방안이 필요하다. 또한 EFDC 모형을 이용한 해수와 담수의 성분비 변화에 대한 경인 아라뱃길의 수질을 예측한 결과, 해수가 많을수록 수질이 BOD, COD 등이 양호 한 것으로 나타났다. 그러나, 염분에 의한 지하수 및 주변환경 변화에 대한 영향을 고려하였을 때, 해수와 담수비를 조절하는 것보다 성분비를 유지하고 유입되는 양을 확대한다면, 경인 아라뱃길의 수질관리는 효과적일 것으로 판단한다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.2
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• pp.141-151
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• 2015

A new rock excavation method using an abrasive injection waterjet system has been developed to enhance the efficiency and reduce the vibration of tunnel excavation. The abrasive feed rate is an important factor for the cutting performance and the economical efficiency of waterjet-based excavation. In this study, various experiments were performed to explore the effects of major process parameters for both the abrasive feed rate and the suction pressure occurring inside the mixing chamber when the abrasives are inhaled. Experimental results reveal that the abrasive feed rate is affected by geometry parameters (abrasive pipe height, length, and tortuosity), abrasive parameters (abrasive particle size), and jet energy parameters (water pressure and water flow rate). In addition, the relation between the cutting performance and the abrasive feed rate was discussed on the basis of the results of an experimental study. The cutting performance can be maximized when the abrasive feed rate is controlled appropriately via careful management of major process parameters.

• KSBB Journal
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• v.22 no.1
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• pp.62-65
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• 2007

New strain development strategy using kinetic models and metabolic control analysis was investigated. In this study, previously reported mathematical models describing the enzyme kinetics of intracellular threonine synthesis were modified for mutant threonine producer Escherichia coli TF5015. Using the modified models, metabolic control analysis was carried out to identify the rate limiting step by evaluating the flux control coefficient on the overall threonine synthesis flux exerted by individual enzymatic reactions. The result suggested the production of threonine could be enhanced most efficiently by increasing aspartate semialdehyde dehydrogenase (asd) activity of this strain. Amplification of asd gene in recombinant strain TF5015 (pCL-$P_{aroF}$-asd) increased the threonine production up to 23%, which is much higher than 14% obtained by amplifying aspartate kinse (thrA), other gene in threonine biosynthesis pathway.

• Korean Journal of Materials Research
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• v.10 no.6
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• pp.445-449
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• 2000

Nickel ferrite $(Ni_{0.75}Fe_{2.25}O_4$ was synthesized by co-precipitation method in order to investigate its behavior under conditions of the reactor coolant system in pressurized light water nuclear power plants. Ammonia or potassium carbonate was used as a solution pH control agent, and aqueous ammonia or potassium carbonate solution or secondary distilled water was used as a co-precipitate washing agent. The effects of the pH control agent and the co-precipitate washing agent on the production yield on the basis of the Ni/Fe molar ratio and the particle characteristics of final products were investigated by XRD, SEM, EDX and XPS. The production yield was almost congruent with that of the initial aqueous mixture in case of using potassium carbonate as a pH control agent, while in case of using ammonia, it was quite changed. The difference seemed to be due to the effects of $Ni^{2+}{\leftarrow}NH_3$complexation in the aqueous solution and of the pH of co-precipitate washing agent.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.4
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• pp.77-81
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• 2020

Resistive RAM (ReRAM) is a strong candidate for the next-generation nonvolatile memories which use the resistive switching characteristic of transition metal oxides. The resistive switching behaviors originate from the redistribution of oxygen vacancies inside of the oxide film by applied programming voltage. Therefore, controlling the oxygen vacancy inside transition metal oxide film is most important to obtain and control the resistive switching characteristic. In this study, we introduced an applying electric field into photochemical metal-organic deposition (PMOD) process to control the oxidation state of metal oxide thin film during the photochemical reaction by UV exposure. As a result, the surface oxidation state of FeOx film could be successfully controlled by the electric field-assisted PMOD (EFAPMOD), and the controlled oxidation states were confirmed by x-ray photoelectron spectroscopy (XPS) I-V characteristic. And the resistive switching characteristics with the oxidation-state of the surface region could be controlled effectively by adjusting an electric field during EFAPMOD process.